This D-shaped enclosure, measuring 22.5 metres in internal diameter, is defined by stone walls that still rise to an impressive 1.5 metres in height despite centuries of weathering. The structure has undergone some reconstruction over the years, though it retains much of its original character amidst the rough grazing land that surrounds it.

Two entrances pierce the enclosure’s defensive walls; one facing northwest and another to the southeast, following a pattern common to many Irish ringforts where multiple access points served both practical and possibly ceremonial purposes. Trees now grow within the enclosure, their roots intertwining with the ancient stonework in a marriage of natural reclamation and human heritage.

Cashels like this one at Altnapaste were typically built between the early medieval period and the 17th century, serving as fortified homesteads for farming families. The substantial stone construction, as opposed to the earthen banks of standard ringforts, suggests this was home to a family of some local standing who could marshal the resources needed for such permanent fortification. Today, it remains a striking feature of the Donegal landscape, offering visitors a tangible connection to the lives of those who once sought shelter within its protective walls.